I am currently using the passive crossovers in the Platinums with the "base" turned down completely and using the sub for fill below 100hz. I want to bi amp the Amazings Listening room is 24'x45' with a 20' vaulted ceiling and good base traps in back (behind listener) 24' wall

I have an ARC EC21 I could use for an active crossover. Anybody have suggestions for crossover points and slope? Any other suggestions? Newbie here. First postingJ

Most have made the crossover upwards of 200 hz, but I personally find the sound more pleasing when I keep it around 160-180 hz. I think the natural falloff of the ribbons to be about 165 hz.

Slope can be 6 dB/octave, but others have used higher slopes with good success. If you're crossover is selectable, you can play with it to find out what you like. FYI, every 6 dB will invert your phase 180 degrees.

You'll want to be able to adjust for ribbon delay to match the woofers (done passively in the passive crossover).

Here are my current crossover points. All crossovers are Linkwitz-Riley 24dB/octave.The Amazing woofers are cut off at 50 Hz because they smoke badly at 100+ dB if you let them play lower. Letting the subs play up to 80 is a no-no, but it works in my tiny room for some reason, ymmv.

Thanks for the quick responses. I have an Audio Research EC21 tube 2 way crossover with a mono bass output. I can figure out the crossover point around 175 or so but I don't know how to make that adjustment for the "ribbon delay". Am I to assume if I have a slope of 12db my phase will be normal? The ARC is not adjustable, I will need to do some soldering...(TNRabbit)

I like the idea of putting a floor on the 12" woofers since I have the VonSweikert (800w) pounding tight well below that 50hz.That is a very impressive "wall of sound" (Martin1970)

Martin1970 wrote:Here are my current crossover points. All crossovers are Linkwitz-Riley 24dB/octave.The Amazing woofers are cut off at 50 Hz because they smoke badly at 100+ dB if you let them play lower. Letting the subs play up to 80 is a no-no, but it works in my tiny room for some reason, ymmv.

TNRabbit wrote:Most have made the crossover upwards of 200 hz, but I personally find the sound more pleasing when I keep it around 160-180 hz. I think the natural falloff of the ribbons to be about 165 hz.

Slope can be 6 dB/octave, but others have used higher slopes with good success. If you're crossover is selectable, you can play with it to find out what you like. FYI, every 6 dB will invert your phase 180 degrees.

You'll want to be able to adjust for ribbon delay to match the woofers (done passively in the passive crossover).

i won't swear although i know many of the words, but , for every 6db it is 90 degrees out so 12 would be 180. i could and may be wrong. just what i remember from rockford fosgate traing in the late 80's.

TNRabbit wrote:Most have made the crossover upwards of 200 hz, but I personally find the sound more pleasing when I keep it around 160-180 hz. I think the natural falloff of the ribbons to be about 165 hz.

Slope can be 6 dB/octave, but others have used higher slopes with good success. If you're crossover is selectable, you can play with it to find out what you like. FYI, every 6 dB will invert your phase 180 degrees.

You'll want to be able to adjust for ribbon delay to match the woofers (done passively in the passive crossover).

i won't swear although i know many of the words, but , for every 6db it is 90 degrees out so 12 would be 180. i could and may be wrong. just what i remember from rockford fosgate traing in the late 80's.